Over the years as accounts servant and secretary I remember a few legacies left to the congregation. Nothing huge but in the two to ten thousand bracket.
One for about £1500 was worded for the "benefit of the poor in the congregation" and it was up to the trustees (elders) to interpret.
It sat "ringfenced" for about five years and I know we used a couple of hundred to pay for "sister gotmorekids" to get to a couple of conventions but eventually we decided that no one in the congregation was really poor (as we have benefits and NHS over here and everyone seemed to be able to afford food, heating, light and a TV!) and so it went on some sound equipment which we felt benefitted the poor along with the rest of the congo.!
I have heard of larger legacies and elders arguing whether it should get sent to the WWW or not. It usually ended up in the GB's coffers one way or another.